<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>计算圆的面积和周长</title>
</head>
<body>
    <script>
        function getArea(r){
            return Math.PI*Math.pow(r,2);
        }
        console.log('半径为5的圆的面积是:'+getArea(5));
        function getLong(r){
            return Math.PI*2*r;
        }
        console.log('半径为5的圆的周长是:'+getLong(5));
    </script>
</body>
</html>